<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }
        div {
            width: 300px;
            height: 300px;
            border-radius: 0 300px 0 0;
            margin: 100px auto;
            background: repeating-radial-gradient(circle at left bottom,#ccc 0%, #ccc 10%, #fff 10%, #fff 20%);
        }
    </style>
</head>
<body>
    <div></div>
</body>
</html>